http://hl7.org/fhir/StructureDefinition/characteristicExpression|5.2.0
An expression that defines the criteria for group membership. This extension can only be used on a Group resource with a membership of `definitional`. When this expression is used, the Group resource cannot have any characteristic elements; this mechanism is exclusive with characteristics. The result of the expression SHALL be boolean-valued. The expression SHALL be parameterized with a `%context` variable that represents the subject being tested for membership. If evaluation of the expression results in `true`, the subject is considered a member of the group.
description: An expression that defines the criteria for group membership. This extension can only be used on a Group resource with a membership of `definitional`. When this expression is used, the Group resource cannot have any characteristic elements; this mechanism is exclusive with characteristics. The result of the expression SHALL be boolean-valued. The expression SHALL be parameterized with a `%context` variable that represents the subject being tested for membership. If evaluation of the expression results in `true`, the subject is considered a member of the group. derivation: constraint name: CharacteristicExpression type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/characteristicExpression'} index: 1 value: choices: [] index: 3 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/characteristicExpression base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.2.0 required: [value]